We study the growth of linear perturbations induced by a generic causal scaling source as a function of the cosmological parameters h , \Omega ^ { m } _ { 0 } and \Omega ^ { \Lambda } _ { 0 } .
We show that for wavenumbers k \mathrel { \hbox to 0.0 pt { \lower 4.0 pt \hbox { $ \sim$ } } \raise 1.0 pt \hbox { $ > $ } } 0.01 % h { Mpc } ^ { -1 } the spectrum of density and velocity perturbations scale in a similar way to that found in inflationary models with primordial perturbations .
We show that this result is independent of the more or less incoherent nature of the source , the small scale power spectrum of the source and of deviations from scaling which naturally occur at late times if \Omega ^ { m } _ { 0 } \neq 1 .